Numerical simulation of seabed response to wave around twin-pile group with different spacings and flow skew angles

The distribution of pile groups affects the wave-structure-seabed interaction (WSSI), which in turn causes the stability of pile structures. Previous WSSI studies focused on the fixed pile group arrangements, lacking a systematic exploration how the pile group arrangements affect the wave-induced dynamic response of the seabed. The present work investigates the wave-induced dynamic response of the seabed induced by wave interaction around twin piles with different pile spacings and flow skew angles using an integrated WSSI model, which is an integrated multiphysics model formulated using the finite volume method (FVM) within the OpenFOAM framework. The changes in free surface elevation, dynamic wave pressure, vertical pore water pressure, vertical effective normal stress and liquefaction depth are carefully assessed. Analysis of the results shows that the blockage effect of upstream pile will decrease with flow skew angle increase from α=0°−90° at a given pile spacing. Furthermore, increasing the flow skew angle strengthens the pore water pressure and liquefaction depth on the front side of upstream pile but weakens it in the center of the twin piles and the upper side of upstream pile. However, the interference effect between twin piles is gradually negligible at 1≤G/D≤3.